U.S. patent number 6,859,674 [Application Number 09/560,607] was granted by the patent office on 2005-02-22 for method for designing and acquiring a machining system based upon performance characteristics.
This patent grant is currently assigned to Ford Motor Company. Invention is credited to Youssef A. Hamidieh, Balachandra Muniyappa, Brij B. Seth.
United States Patent |
6,859,674 |
Seth , et al. |
February 22, 2005 |
Method for designing and acquiring a machining system based upon
performance characteristics
Abstract
A method for designing and acquiring a machine by the use of
benchmark machines which perform a certain function or operation in
a desired manner. Certain locations are analyzed on the benchmark
machines and vibration measurements and/or impact tests conducted
on these locations which allow certain attributes or
characteristics to be respectively assigned to these locations. The
new machine is designed to improve upon these respective
characteristics or attributes, thereby performing the operation in
a highly accurate and reliable manner.
Inventors: |
Seth; Brij B. (Canton, MI),
Hamidieh; Youssef A. (Bloomfield Hills, MI), Muniyappa;
Balachandra (Westland, MI) |
Assignee: |
Ford Motor Company (Dearborn,
MI)
|
Family
ID: |
34135404 |
Appl.
No.: |
09/560,607 |
Filed: |
April 28, 2000 |
Current U.S.
Class: |
700/97; 700/108;
702/186 |
Current CPC
Class: |
B23Q
17/00 (20130101); B23Q 17/0995 (20130101) |
Current International
Class: |
G06F
19/00 (20060101); G06F 019/00 () |
Field of
Search: |
;700/97,108,160,173,174,193 ;702/182,183,184,186,56 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Picard; Leo
Assistant Examiner: Rapp; Chad
Attorney, Agent or Firm: Kelley; David B.
Claims
What is claimed is:
1. A method for designing and acquiring a machine comprising the
steps of: identifying at least a first machine; operating said at
least said first machine; testing said at least said first machine;
acquiring data by said testing of said first machine; designing a
second machine by use of said data; building said second machine;
evaluating said second machine by the use of said data, wherein the
step of evaluating said second machine further has the step of
performing a finite element analysis of said second machine using
the said data; and acquiring said second machine based upon said
evaluation.
2. The method of claim 1 further comprising the step of: modifying
said second machine to meet certain performance criteria obtained
from said evaluation.
3. The method of claim 2 when said first machine has a certain
stiffness and wherein second data further comprises a measure of
said stiffness.
4. The method of claim 3 wherein a portion of said second machine
receives a tool and wherein said portion vibrates by a certain
amount and has a certain stiffness, and wherein said second data
comprises said stiffness of said portion and a measure of said
vibration of said portion.
5. The method of claim 3 further comprising the steps of: placing
said second machine in a launch area; operating said second
machine; acquiring third data by operating said second machine;
comparing said third data to said second data; and modifying said
second machine based upon said comparison.
6. The method of claim 5 further comprising the steps of: placing
said second machine within a manufacturing plant; operating said
second machine; acquiring fourth data by operating said machine
within said manufacturing plant; comparing said fourth data to said
second data; and modifying said second machine based upon said
comparison of said fourth data with said second data.
7. The method of claim 3 wherein said stiffness is measured by use
of a static force loading test.
8. The method of claim 1 wherein a plurality of machines comprises
plunge cut machines.
9. The method of claim 1 wherein a plurality of machines comprises
hobbing machines.
10. The method of claim 1 further comprising the step of: modifying
the second machine in accordance with results of the finite element
analysis.
11. The method of claim 10 further comprising the step of:
modifying a material used in the design of the second machine.
12. The method of claim 10 further comprising the step of:
modifying a structure used in the design of the second machine.
13. The method of claim 10 further comprising the step of:
modifying a shape used in the design of a portion of the second
machine.
14. The method of claim 10 further comprising the step of:
increasing a thickness of a portion of said second machine.
15. A method for designing a machine comprising the steps of:
select a first machine; specify at least one location on said first
machine; characterizing said at least one location by a first
value; designing a second machine having a second location;
characterizing said second location by a second value, wherein the
second value may be determined by using static force loading;
comparing said second value with said first value using finite
element analysis to improve design characteristics of the second
machine; and approving said design based upon said comparison of
said first value with said second value.
16. The method of claim 15 when said first machine has a certain
stiffness at said at least one location and wherein said first
value is substantially equal to said certain stiffness.
17. The method of claim 15 when said first machine vibrates by a
certain amount at said at least one location and wherein said
second value is substantially equal to said certain amount.
18. The method of claim 15 further comprising the steps of building
said second machine; testing said second machine in order to
measure said second value; and acquiring said second machine only
if said measured second value resides below a certain threshold
value.
19. A method for purchasing a machine comprising the steps of:
selecting a benchmark machine which selectively performs a desired
function; identifying a certain first portion of said benchmark
machine; measuring a certain attribute level of said first portion
using at least one of a static force loading test and an impact
test; and designing a second machine which is substantially similar
to said benchmark machine and which includes a first portion which
differs from said first portion of said benchmark machine using
finite element analysis, effective to allow said second machine to
perform said desired function in a reliable and accurate manner
wherein the step of designing said second machine comprises the
step of modifying at least one of a material, a structure, and a
shape used in the design of said second machine to improve upon at
least one attribute of said benchmark machine.
20. The method of claim 19 wherein said certain attribute level
comprises stiffness.
21. The method of claim 19 wherein said certain attribute level
comprises an amount of vibration.
22. The method of claim 21, wherein said certain attribute level is
measured by use of an impact test.
23. The method of claim 21 wherein said certain attribute level is
measured by measuring vibration levels while said benchmark machine
is idling a nd performing machining operations.
24. The method of claim 19 wherein said certain said portion of
said benchmark machine comprises a tool reception portion.
25. The method of claim 19 wherein said benchmark machine comprises
a spindle and wherein said certain portion comprises said
spindle.
26. The method of claim 19 wherein said benchmark machine comprises
a hobbing machine.
Description
(1) FIELD OF THE INVENTION
This invention generally relates to a method for designing and
acquiring a machine system based upon performance characteristics
and more particularly, to a method for designing and acquiring a
machine tool based upon benchmarking of existing machine tools
which operatively reside within a manufacturing facility or plant
or outside at a supplier's floor, such benchmarking being
accomplished by respectively placing these machine tools in an idle
state or condition and in an operative or "loaded" state or
condition and noting the response vibrations associated with
operation and/or acquired from impact testing. The invention
further relates to designing and acquiring or purchasing a machine
or a machine system (i.e., a machine having several interconnected
components) having certain desirable characteristics and attributes
which substantially insures that such a machine system has a
certain desired structural integrity associated with the assembly
comprising a tool holder, spindle, slides, gibs, ball screw or
linear motor drive, fixturing elements, and machined components
together with the machine bed.
(2) BACKGROUND OF THE INVENTION
Machine tools are used to perform a wide variety of machining tasks
such as, and without limitation, creating an item and/or
"machining" or frictionally engaging an item or "workpiece" in
order to shape the item in some desired manner.
Typically, a "transfer line" type machine is adapted or "designed"
to perform a single task or function while machining centers or
assemblies are capable of being selectively programmed to perform a
variety of different types of machining operations.
For example, one type of transfer line machine tool includes a
selectively movable spindle which is adapted to selectively receive
a tool and to rotate the tool as the tool selectively engages the
workpiece or item, effective to "machine" or shape the workpiece or
item in a desired manner. The "shaped" item may then be transported
to another machine where it is subjected to further machining or
another type of operation. Hence, several dissimilar machines may
be employed within an overall process to cooperatively produce such
a desired item and/or to cooperatively perform some desired
machining tasks on a component. Such machining operations may
comprise a number of widely varying or different types of
operations which are performed upon the component, such as drilling
or face milling. Alternatively, these operations may be
substantially similar but may be selectively performed at different
depths of the component and/or cause the component to be cut at
different depths and/or may utilize different machining parameters
in order to acquire the desired surface finish characteristics.
Examples of such operations include face milling, roughing,
semi-finish and finishing operations. Moreover, it is also
relatively likely that in a relatively high volume production
environment, a complete machining operation on a component is
performed by more than one machining center and with more than one
"set-up".
The ability of a machine tool to accurately and desirably perform
its respective function is typically dependent upon certain
attributes or characteristics associated with the machine tool
and/or certain attributes and/or characteristics associated with
the various components of the machine tool. Such components
typically comprise a tool holder, spindle, slides, gibs, ball screw
or linear motor drive, fixturing elements, and machined components
together with machine bed. Moreover, the quality of the machined
components is typically dependent upon the characteristics of the
integral or overall "system" of the machining tool which is
comprised of many different and diverse types of interconnected
elements and/or components. For example, machine tool components
having high stiffness and low vibration characteristics typically
enable a machine tool to perform a task in a more accurate and
reliable manner. Thus, a large variance exists between machine
tools which are adapted to perform the same overall task or
function but which are manufactured or produced by different
manufacturers, which have a respectively different configuration or
design, and which are constructed or created by use of a diverse
array of different components.
The process or methodology for designing and/or acquiring a machine
tool is relatively and typically complicated due to the large
number of interconnected components which are employed within the
machine and the relatively intricate functional relationship
required of these components. The use of such a large number of
interconnected components reduces the likelihood that the overall
function or task performed by the machine tool is optimized (i.e.,
is reliably and repeatably performed with a certain accuracy)
across different machine tools. Further, since the overall
performance of a machine tool varies as it is used due to, by way
of example and without limitation, component wear, or structural
fatigue, it is difficult to ascertain whether a certain newly
manufactured machine will reliably and repeatably perform a certain
function, task, and/or operation in a desired manner during its
entire operating life or during some other predetermined interval
of time.
There is therefore a need for an effective benchmarking of existing
machine tools and/or components which are operatively disposed
within a manufacturing facility and/or plant and which have
enhanced and/or desirable performance characteristics together with
certain "sub-par" or undesirable capabilities and/or
characteristics in order to derive design criteria for the
fabrication and assembly of different components of the machine
tool in an efficient and cost effective manner. There is also a
need for a method for providing a machining system which
accomplishes a desired task, operation, or function in a
substantially and highly accurate manner during its operating life.
There is also a need for a method for evaluating certain
characteristics or attributes of a machine tool before such a
machine tool is purchased, or after it is purchased but before it
is shipped to a certain manufacturing plant, in order to
substantially increase the likelihood that a machine that is
purchased or is acquired by a business organization, will meet the
needs and requirements of the organization and, more particularly,
will continue to perform a function, task, and/operation in a
desired manner during its operating life.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide a method
for designing and acquiring a machine based on benchmarking of
existing machines which are operatively disposed within a
manufacturing plant or at a supplier's floor under idle and
machining loads, and further based upon an analysis of the response
characteristics of some or all the various machines components
operatively contained within the machine.
It is a second object of the present invention to provide a method
for efficiently designing a machine tool in a manner which
overcomes the various and previously delineated drawbacks of prior
methods.
It is a third object of the present invention to provide a method
for designing a machine tool having an assemblage of different
sub-components which cooperatively perform a certain function,
operation, and/or task in a desired manner.
It is a fourth object of the present invention to provide a method
for reliably evaluating a machine tool, effective to allow a
machine tool to be acquired or purchased by a business organization
in a manner which substantially ensures that the machine will meet
the needs and the requirements of the purchaser.
According to a first aspect of the present invention, a method is
provided for benchmarking and characterizing existing machine tools
and components of machine tools with enhanced performance for
producing quality parts and extended machine uptime and durability
and those which do not perform adequately in order to establish
design criteria for cost effective and efficient design and
fabrication. The method includes the steps of: identifying target
machines; on each machine tool performing stiffness
characterization of different components with impact testing or
static force loading; on each machine tool operating the spindles
at rated speed while idle (no cutting) and capturing vibration
signatures on spindle housing in the different directions; on each
machine tool, performing normal machining operation and capturing
the vibration signatures for the entire machining cycle on
different components of the machine tool and in different
directions; analyzing the stiffness data for the different
components and the vibration data in time and frequency domain;
repeating the process on other benchmark machine tools; tabulating
the results for all the machine tools and components with enhanced
performance characteristics and with deficient characteristics;
establishing cost effective/efficient design criteria for the
critical machine tool components based on stiffness and vibration
characteristics; establishing a machine tool design iteration loops
for all the critical components consisting of a proposed design
followed by Finite Element Analysis (FEA), or other structural CAE
analysis followed by design modifications based on deficient
findings. Then following this by another round of structural
analysis; fabricating the sub-components and impact testing the
critical sub-components at suppliers floor before assembly; and
assembling the machine tool and characterizing it with stiffness
testing and capturing the vibration signatures and comparing with
desirable machine tool requirements.
These and other features, aspects, and advantages of the present
invention will become apparent from a reading of the following
detailed description of the preferred embodiment of the invention
and by reference to the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart illustrating a sequence of steps comprising
the methodology of the preferred embodiment of the invention;
FIG. 2 is block diagram of a specific valve seat and guide
machining process machine as an example which is selectively used
to provide desirable vibration performance data based on
benchmarking in accordance with the methodology of the preferred
embodiment of the invention;
FIG. 3 is a block diagram of a specific valve seat and guide
machining process machine as an example which is shown in FIG. 2
and which is selectively used to provide desirable stiffness
performance data based on benchmarking in accordance with the
methodology of the preferred embodiment of the invention;
FIGS. 4(a)-(g) illustrate an impact test which is performed upon
the machine shown in FIGS. 2 and 3, and the resulting stiffness
analysis which is performed in accordance with the methodology of
the preferred embodiment of the invention;
FIGS. 5(a)-(c) illustrate a vibration test which is performed upon
the machine shown in FIGS. 2 and 3 and the resulting vibration
analysis which is performed in accordance with the methodology of
the preferred embodiment of the invention;
FIG. 6 is a perspective view of a conventional hobbing machine to
which the methodology of the preferred embodiment of the invention
has been applied;
FIG. 7 is a graph comparing various vibration values associated
with the hobbing machine shown in FIG. 6 before and after the
methodology of the preferred embodiment of the invention has been
applied to the machine; and
FIG. 8 is a graph comparing various minimum dynamic stiffness
values of the hobbing machine which is shown in FIG. 6, before and
after the methodology of the preferred embodiment of the invention
has been applied to the machine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE
INVENTION
Referring now to FIG. 1, there is shown a flowchart 10 comprising
and/or illustrating the sequence of steps associated with the
methodology of the preferred embodiment of the invention.
Particularly, flowchart 10 includes a first step 12 in which one or
more "target" machines are selected which have been previously
purchased or acquired and/or analyzed over some predetermined
period of time and which were found to perform a desired function
or operation in an acceptable manner.
In the preferred embodiment of the invention, the selected machines
have enhanced performance characteristics which allow the machines
to produce quality parts and have "extended machine uptime" and
durability attributes (i.e., the machines are respectively able to
operate for a relatively long period of time without requiring
maintenance or experiencing failure). These machines may be
referred to as the "benchmark" machines. As is more fully and
completely delineated below, it will be these machines which will
be used to design a new machine (e.g., to select and assemble
various sub-components to form a new machine) in a manner which
will allow the newly designed machine to have certain desired
characteristics and attributes which will allow the newly designed
machine to perform these operations even more accurately and
reliably than the benchmark machines. Hence, by beginning the
machine design process with a previously designed machine, which is
known to operate in a desirable manner, one is able to greatly
enhance the overall machine design process by providing design
criterias and improve upon an even previously acceptable operating
performance. Moreover, this process also allows components,
operatively residing within the benchmark machines to be modified
in a manner which allows the benchmark machines to perform in a
superior or "enhanced" manner.
In one non-limiting embodiment of the embodiment, other machines
having "sub-par" performance characteristics are also analyzed and
compared with those benchmark machines having respectively desired
performance characteristics in order to establish design criteria
for the cost effective and efficient design and/or acquisition of
new machines or for improving performance of the existing "sub-par"
machines.
One non-limiting example of one such benchmark machine is shown in
FIG. 2. As shown, machine 40 includes a selectively movable or
rotatable spindle 42 which is adapted to selectively receive a tool
44 and which selectively moves and/or rotates the received tool 44
against a workpiece 46 in order to shape or form the workpiece 46
in a desired manner. As shown, workpiece 46 is typically clamped or
mounted to a fixture 56 in a conventional manner. The spindle
housing 48 rests upon a machine slide 54, which is typically and
movably mounted to a machine base 57. The machining operations or
processes may include the performance of different operations upon
the workpiece 46, such as and without limitation, drilling or face
milling. Alternatively, based upon requirements, substantially the
same machining operations are performed at different depths of
"cut" within workpiece 46 and by use of different machining
parameters in order to acquire the desired surface finishes.
Examples of such operations include face milling, roughing,
semi-finish and finishing type operations. In a typical machining
facility, a complete machining process which is performed upon
workpiece 46 may be accomplished at more than one machining center
or station and with more than one "set-up" or machine.
Additionally, each machine and/or machining center may be
selectively programmed to perform different machining operations.
It should be appreciated that other types of machines may be used
as a benchmark machine by the methodology of the preferred
embodiment of the invention, and nothing in this Application should
restrict the methodology of the preferred embodiment of the
invention to the machine or the type of machine which is shown in
FIG. 2.
Step 14 follows step 12 and in this step "target" locations, areas
or components of the benchmark machine 40 are chosen for sensor
locations, data capture, and vibration and dynamic stiffness
analysis. In one non-limiting embodiment, these areas or locations
include the area or location 50 in which the machine 40 receives
tool 44. Different areas, locations and/or components of machine 40
may be used for this characterization (e.g., tool holders, spindle,
slides, gibs, ball screws, linear motor drives fixturing elements,
and other portions of machine 40 having attributes or
characteristics which effect the quality of machined components).
Moreover, in another non-limiting embodiment, a machine location or
area is typically chosen for characterization if it "interfaces
with" or receives another section or portion of the machine and/or
if it physically moves or controls the movement of a tool or other
object which is used to perform some desired function or action.
Various desirable or benchmark vibration levels for the machine 40
are shown in FIG. 2 and various desirable or benchmark minimum
dynamic stiffness levels for machine 40 are shown in FIG. 3. Also
respectively shown in FIGS. 2 and 3, are the benchmark vibration
and stiffness levels of the fixture 56 and workpiece 46.
Step 16 follows step 14, and in this step, these attributes or
characteristics (i.e., vibration and stiffness) are measured,
assigned, and associated with each of the locations/components
which are identified in step 14. Particularly, in one non-limiting
embodiment of the invention, the amount of minimum dynamic
stiffness and operational vibration are two attributes which are
measured for each location/component which is specified in step 14
(e.g., components having a relatively high stiffness and low
vibration characteristics are desired). In one non-limiting
embodiment, a "stiffness" characterization of different components
is performed on each machine by impact testing and/or static force
loading. The vibration characterization may be established by use
of a vibration sensor. Creation of these characterizations are
shown more fully below.
One example of a "stiffness" characterization or impact test on a
machine 40 is illustrated in FIGS. 4(a)-(g). Particularly, as shown
in FIG. 4(a), a calibrated hammer 70 having a force transducer is
used to impact or strike various portions of the machine 40, such
as the tool 44 with a certain predetermined force which is measured
and recorded by the transducer. A conventional sensor 72 (e.g., an
accelerometer or other vibration sensor) is operatively disposed on
the tool 44 and measures the vibration response or characteristic
of the tool 44 when struck by the hammer 70. Graphs 74-84 represent
values measured during the "impact" test. Particularly, graph 74 of
FIG. 4(b) illustrates the force input measured by the transducer;
graph 76 of FIG. 4(c) illustrates the vibration response of the
tool measured by sensor 72; graph 78 of FIG. 4(d) illustrates the
force spectrum of the impact; graph 80 of FIG. 4(e) illustrates the
vibration spectrum of the response; graph 82 of FIG. 4(f)
illustrates dynamic stiffness magnitude plotted against frequency;
and graph 84 of FIG. 4(g) illustrates the phase characteristic of
the signal. Graphs 74-84 cooperatively provide a measure of the
dynamic stiffness of the portion of the tool 72 which is impacted
by the hammer 70. In this manner, the stiffness of the tool 44 may
be analyzed. Similarly, the stiffness of the other respectively
impacted locations may also be achieved.
Referring now to FIGS. 5(a)-(c), in one non-limiting embodiment,
the vibration signature or response for the "target" machines 40 is
also measured in step 16 at each of the various locations shown in
FIG. 2.
Particularly, as shown in FIG. 5(a), the vibration signature or
response for machine 40 (e.g., for the integral machine or system
and/or for different components or areas of the machine) is
measured in a conventional manner (e.g., by the use of a vibration
sensor) while machine 40 is operated at rated speeds while machine
40 is idling (e.g., not cutting), and while machine 40 is
performing machining operations over the entire machining cycle and
in different directions. A time domain analysis 86 of the vibration
signature of the integral system is illustrated in FIG. 5(a). Graph
88 of FIG. 5(b) illustrates a frequency domain analysis of the
integral system response while machine 40 is idling, and graph 90
of FIG. 5(c) illustrates a frequency domain analysis of the
integral system response while machine 40 is performing a machining
operation. In this manner, the vibration level at various portions
or locations of the machine 40 may be analyzed.
Based upon these measured attributes and characteristics, in step
18, the "benchmark" or "minimum dynamic stiffness and vibration
guidelines" which are used to design the new machine are
established. That is, the stiffness data and the vibration data for
the different locations and/or components is analyzed for the
tools/machines having enhanced performance characteristics and for
those with deficient characteristics. In the preferred embodiment
of the invention, the new machine must typically perform
substantially the same task or function as the benchmark machine
but having certain characteristics or attributes which improve upon
the measured characteristics or attributes in step 16. In one
non-limiting embodiment, the new machine may be a substantial
replica of the benchmark machine but differing from the benchmark
machine at those target locations or components in order to allow
or cause these areas or locations, on the new machine, to have
attributes or characteristics which allow the new machine to
perform its function in a more accurate and reliable manner than
the benchmark machine. Moreover, the foregoing analysis allows a
business enterprise to modify a component and/or a portion of the
benchmark machine in order to enhance the performance of the
benchmark machine.
Hence, in step 20 a design of the new machine is accomplished by
use of the benchmark machine and by modifying the material,
structure, and/or shape or geometry of the respective locations,
such as location 50, 52, and 42 of the benchmark machine or the new
machine to improve upon the stiffness and reduce or minimize
respective operational vibration (i.e., these respective locations
50, 52, 42 may have an increased thickness over those locations 50,
52, 42 on the benchmark machine in order to increase stiffness). In
the preferred embodiment, the stiffness and vibration
characteristics are used to establish cost effective and efficient
design criteria for the new machine and/or for components of the
new machine.
Step 22 follows step 20, and in this step, the new design is
evaluated by use of a computer simulation and/or computer aided
design system in order to determine whether the new design does
provide these improved attributes and characteristics.
Particularly, during the design process a Finite Element Analysis
32 or other structural analysis may be accomplished upon these
components, locations or areas 42, 50 and 52 of the new machine,
and in step 34, is compared with a similar Finite Element Analysis
which may be accomplished on the benchmark machine at similar or
analogous components or locations. The design is modified in step
24, if necessary, based on deficient findings, to further improve
upon these attributes and characteristics and an evaluation is
accomplished on this new design. The structural analysis, (e.g.,
steps 22, 32, 34, 24) may be repeated several times on the modified
design until a satisfactory design is achieved.
After the design appears to produce a machine having attributes
and/or characteristics which allow it to operate in a superior
manner to the benchmark machine, step 22 is followed by step 26 in
which the machine is actually built or constructed. In one
non-limiting embodiment, the sub-components of the machine are
built first and tested (e.g., impact tested) before assembly of the
entire machine. Step 28 follows step 26, and in this step, the
machine is tested in a launch or staging area or supplier's floor
in order to simulate the operational environment in which the
machine is to be utilized. In the preferred embodiment, the
assembled machine is characterized with stiffness testing and
capturing the vibration signatures and comparing the results with
desirable machine tool requirements. Step 30 follows step 28, and
in this step, the machine is modified, if necessary, to further
improve upon the operational performance of the machine. Step 38
follows step 28, and requires that the machine be tested on the
plant floor or the actual operating environment in which the
machine is to be used. After the machine has been tested, it may be
purchased or acquired by a business organization. In this manner, a
business organization is substantially assured that it is acquiring
a machine which will meet its needs and reliably perform a desired
function.
The efficiency of the methodology 10 may best be shown by reference
to FIGS. 6-8. Particularly, as best shown in FIG. 6, a typical
hobbing machine 100 may be initially benchmarked. Particularly,
hobbing machine 100 includes a selectively movable hob portion 102
which is movably coupled to a first or "outboard" bearing and
housing 104 and to a second or "inboard" bearing and housing 106.
Units 104 and 106 are coupled to a portion 108 of machine of
machine 100. Further, machine 100 includes a second portion 110
having a quill support member or portion 112 which is adapted to
cooperate with a lower spindle 114 to receive a workpiece 116. In
operation, one of the members of portions 108 may be moved relative
to the other portion, thereby allowing the hob portion 102 to
selectively contact the workpiece 116.
As shown best in FIG. 7, the vibration level of the bearing
housings 104 (i.e., "OB Housing") and 106 (i.e., "IB Housing") are
reduced in the various directions or axes illustrated in FIG. 6, as
are the vibration of the quill 112 and the deburring tool (not
shown) by applying the methodology of the preferred embodiment of
the invention to the machine 100. Further, as best shown in FIG. 8,
the stiffness of the hobbing tool is also improved at each position
shown in FIG. 6 form 12 o'clock to 6 o'clock by applying the
methodology of the preferred embodiment of the invention to the
machine 100.
It should be appreciated that the present method may be used with
virtually any type of machine, including but not limited to,
"plunge cut" machines and hobbing machines. It should further be
understood that the invention is not limited to the exact
construction and method which has been previously delineated but
that various changes and modifications may be made without
departing from the spirit and the scope of the inventions as are
more fully delineated in the following claims.
* * * * *